Gates has specifically asked the study group to include the opinions of gay men and lesbians who serve in the military. That's a challenge, since under the law they must keep their sexual orientation a secret if they want to keep their jobs. (It's anybody's guess how many gays are in uniform, but one recent estimate pegged the number at 2 percent of military personnel, or about 66,000 people.)

In a phone interview Wednesday, Ham said his group would probably employ a third-party pollster to reach out to gay service members and survey them under a guarantee of confidentiality. "These groups have some pretty masterful ways of reaching out to what they call hidden groups in larger communities," he said.

Ham said the survey would have to occur at arm's length for practical and legal reasons. "We know that a serving Department of Defense official, especially one in uniform, cannot be the one to do this," he said. If a gay soldier "were to disclose to me their sexuality," he added, "then I'd almost certainly be required to pursue that" by opening a formal investigation that could lead to discharge.

Not everyone at the Pentagon agrees. Army Secretary John M. McHugh told reporters Wednesday that he has been gauging troops' sentiment on "don't ask, don't tell" recently. In response, he said, some have volunteered that they are gay. He said he declined to take action against them, reasoning that if he hadn't asked, they wouldn't have told.

"What I'm trying to do is show the troops that, yes, it's okay to talk about this," he said. "I just felt it would be counterproductive . . . to take disciplinary action against someone who spoke openly and honestly."

Last week, Gates called Mixon's comments "inappropriate." Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, concurred and said that if commanders disagree with policy changes, they should not resort to political advocacy but rather "vote with your feet" by resigning.

Since then, however, Mixon appears to have undergone a political rehabilitation. On Wednesday, McHugh said that Mixon had been advised that his letter was "inappropriate" but that he would not receive a formal reprimand.

Another general who has been at odds with Gates and Mullen over "don't ask, don't tell" is James T. Conway, commandant of the Marine Corps. Conway has told Congress that the law should not be changed. Last week, he said that even if it is, he will not force straight Marines to live with gay ones in their military quarters, citing what he called "overwhelming" opposition in the Corps to such an arrangement. Conway, however, has not drawn any official rebukes for his views.

Ham said the military could resolve concerns over housing. He said a much tougher challenge would be to determine whether same-sex partners or spouses should receive recognition or benefits, given the fast-changing and conflicting array of state and federal laws regarding gay marriage.